Biomaterial Database

Rifampin and warfarin: a drug interaction. 1975

J A Romankiewicz, and M Ehrman

The drug interaction between warfarin and rifampin is not well known. Rifampin has been reported to increase the warfarin requirements in human subjects ingesting these agents simultaneously. The concomitant administration of rifampin and warfarin resulted in the need for an unusually high maintenance dose of warfarin (20 mg per day) in order to produce a therapeutic effect. Withdrawal of rifampin decreased the warfarin requirement by 50%. This effect may be mediated by the ability of rifampin to induce microsomal enzymes and, thus, the catabolism of warfarin. The effect of rifampin on the warfarin requirement of our patient appeared to be maximal 5 to 7 days after the initiation of rifampin and extended a similar length of time after rifampin withdrawal. This interaction appears to be clinically significant.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011517	Prothrombin Time	Clotting time of PLASMA recalcified in the presence of excess TISSUE THROMBOPLASTIN. Factors measured are FIBRINOGEN; PROTHROMBIN; FACTOR V; FACTOR VII; and FACTOR X. It is used for monitoring anticoagulant therapy with COUMARINS.	Quick Test,Russell's Viper Venom Time,Thrombotest,Russell Viper Venom Time,Russells Viper Venom Time,Prothrombin Times,Test, Quick,Time, Prothrombin,Times, Prothrombin
D011655	Pulmonary Embolism	Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.	Pulmonary Thromboembolism,Thromboembolism, Pulmonary,Embolism, Pulmonary,Embolisms, Pulmonary,Pulmonary Embolisms,Pulmonary Thromboembolisms,Thromboembolisms, Pulmonary
D004347	Drug Interactions	The action of a drug that may affect the activity, metabolism, or toxicity of another drug.	Drug Interaction,Interaction, Drug,Interactions, Drug
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012293	Rifampin	A semisynthetic antibiotic produced from Streptomyces mediterranei. It has a broad antibacterial spectrum, including activity against several forms of Mycobacterium. In susceptible organisms it inhibits DNA-dependent RNA polymerase activity by forming a stable complex with the enzyme. It thus suppresses the initiation of RNA synthesis. Rifampin is bactericidal, and acts on both intracellular and extracellular organisms. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1160)	Rifampicin,Benemycin,Rifadin,Rimactan,Rimactane,Tubocin
D014859	Warfarin	An anticoagulant that acts by inhibiting the synthesis of vitamin K-dependent coagulation factors. Warfarin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism, and atrial fibrillation with embolization. It is also used as an adjunct in the prophylaxis of systemic embolism after myocardial infarction. Warfarin is also used as a rodenticide.	4-Hydroxy-3-(3-oxo-1-phenylbutyl)-2H-1-benzopyran-2-one,Aldocumar,Apo-Warfarin,Coumadin,Coumadine,Gen-Warfarin,Marevan,Tedicumar,Warfant,Warfarin Potassium,Warfarin Sodium,Potassium, Warfarin,Sodium, Warfarin